Draft-box eob steam-engines



STATES' PATENT OFFICE;

ANDREW M. EASTWICK, OF PHILADELPHIA, PENNSYLVANIA.

DRAFT-BOX FOR STEAM-ENGINES.

Specification of Letters Patent No. 674, dated April 5, 1838.

To all whom t may concern: y

Be it known that I, ANDREW M. EAST- wIoK, of the city of Philadelphia, in the State of Pennsylvania, machinist, have invented a new and improved mode of con-V structing a draft-box to be applied to the chimney of locomotives orl other steam-eng'ines for the purpose of increasing the draft by the action of the waste steam; and I do hereby declare that the following is a full and exact description thereof. It has been the practice heretofore, when draft boxes have been employed for the purpose of increasing the intensity of the re by accelerating the rapidity of the current ofl the chimney, to sufer the waste steam from each of the cylinders of the engine to escape from them into one common compartment or single draft boX, whence it passed through suitable tubes into the chimney, in this mode of procedure, however, it has been found that there is an interference of the force of the escape steam from one cylinder with that of the other so that the greatest useful eect is not produced.

To obviate this diliculty I divide my improved draft box into two compartments by means of a partition or diaphragm so formed and arranged as to cut olf all interfering communication between the two and to obtain the full effect of the waste steam. In the acompanying drawing, which represents a vertical section through the center of the draft boina and a are the two compartments into which it is divided, by means of the partition Z1, 5,'-the waste steam from one of the cylinders Yenters the compartment a, and from the other cylinder the compartment af, through proper openings constructed for that purpose in the usual way. From the compartment a, the tubes c, c, 0, lead through the compartment a, and into the chimney; while from the compartment a', the tubes c', c', c', likewise conduct the steam into the chimney. At the escape end, the tubes c, c, c, c, are usually narrowed to increase the intensity of the blast.

All that I claim as my invention and wish to secure by Letters Patent is The division of the draft box into two i distinct compartments, in the manner and for the purpose set forth; -not intending to confine myself to any particular form of apparatus, but to varythis as I may think 

